Various techniques have been developed to separate particles from one another. For example, using rotating disk separators for grain processing, sand and gravel sorting, and beverage sedimentation removal are well known. With respect to biological samples, centrifugal techniques have been employed. For instance, U.S. Pat. No. 6,221,655 to Fung et al. discloses a spin filter assembly for isolating and analyzing molecules and compounds present in biological and non-biological samples. In particular, Fung discloses that the spin filter may be inserted within a centrifuge holder and spun such that materials having a larger pore size than a filter at the bottom of the spin filter are retained therein. These particles may then be removed from the spin filter for further processing and analyzing. The smaller sized materials pass through the filter and collect at the bottom of the centrifuge holder and may be later discarded.
Furthermore, Ficoll® separation is a known technique that is used to separate particles within a biological sample. Generally, Ficoll® separation involves using centrifugation and density gradients to form layers of different types of particles having equivalent densities. Following separation into layers, each layer may be analyzed individually. Ficoll® separation is a slow process that may be used to separate blood into its components.
Therefore, it may be advantageous to provide a method and an apparatus for separating particles within a biological specimen. In addition, it may be advantageous to provide a method and an apparatus for collecting particles that have been separated within a biological specimen. Moreover, it may be advantageous to provide a method and an apparatus that is cost efficient and that combines several stages of processing.